The substituents R₁ and R₂ for nine peptides are listed in the table given below. How many of these peptides are positively charged at pH = 7.0 ?

Peptide	$${R_1}$$	$${R_2}$$
I	H	H
II	H	$$C{H_3}$$
III	$$C{H_2}COOH$$	H
IV	$$C{H_2}CON{H_2}$$	$${(C{H_2})_4}N{H_2}$$
V	$$C{H_2}CON{H_2}$$	$$C{H_2}CON{H_2}$$
VI	$${(C{H_2})_4}N{H_2}$$	$${(C{H_2})_4}N{H_2}$$
VII	$$C{H_2}COOH$$	$$C{H_2}CON{H_2}$$
VIII	$$C{H_2}OH$$	$${(C{H_2})_4}N{H_2}$$
IX	$${(C{H_2})_4}N{H_2}$$	$$C{H_3}$$

When the following aldohexose exists in its D-configuration, the total number of stereoisomers in its pyranose form is ____________.

Let z be a complex number such that the imaginary part of z is non-zero and $$a\, = \,{z^2} + \,z\, + 1$$ is real. Then a cannot take the value

If $$\overrightarrow a ,\overrightarrow b $$ and $$\overrightarrow c $$ are unit vectors satisfying
$${\left| {\overrightarrow a - \overrightarrow b } \right|^2} + {\left| {\overrightarrow b - \overrightarrow c } \right|^2} + {\left| {\overrightarrow c - \overrightarrow a } \right|^2} = 9,$$ then $$\left| {2\overrightarrow a + 5\overrightarrow b + 5\overrightarrow c } \right|$$ is